This invention relates to a method and an apparatus for attaching a belt-like member-onto a circumference of a drum, while the belt-like member is being transferred by a conveyor.
A method and apparatus for attaching a belt-like member onto a drum has been known, for example, as disclosed in Japanese Patent Application Laid-open No. 62-11,634. The apparatus of the prior art comprises a forming drum, driving means for rotatively driving the drum, transfer means for transferring an unvulcanized tire member held by a plurality of absorbers to a cylindrical outer surface of the forming drum, a first detector for detecting a position of a forward end of the unvulcanized tire member wound about the forming drum, a second detector for detecting a position of a rear end of the unvulcanized tire member relative to the transfer means when the rear end is wound about the drum, and control means for controlling the driving means and the transfer means to elongate the unvulcanized tire member corresponding to a shortage determined by arithmetic operation on the basis of detecting signals from the first and second detectors.
In a case where an unvulcanized tire member is wound and formed on the forming drum with overlapping ends using the apparatus of the prior art, the forming drum is rotated and the transfer means is moved in synchronism with a circumferential speed of the forming drum. The unvulcanized tire member held by the absorbers is supplied onto the outer circumferential surface of the drum or an outer circumferential surface of the unvulcanized tire member already wound about the forming drum. When the unvulcanized tire member has been wound a certain amount on the outer circumferential surface, a forward end of the unvulcanized tire member is detected by the first detector and a rear end thereof is then detected by the second detector. Detecting signals obtained in the detections are fed to the control means. The control means computes the shortage in length of the unvulcanized tire member or the difference between the circumferential length of the drum or wound member plus a predetermined overlapping length and an overall length of the unvulcanized tire member (which has been cut in the length slightly shorter than the circumferential length of the drum) plus the predetermined overlapping length. A control signal obtained in this arithmetic process in the control means is fed to at least one of the driving means for the forming drum and driving means for the transfer means.
As a result, the forming drum and the transfer means are moved relative to each other to pull the unvulcanized tire member so that the length of the unvulcanized tire member is corrected. Thereafter, the rear end portion of the unvulcanized tire member is wound on the outer circumferential surface of the forming drum.
With such an apparatus of the prior art, the length of the unvulcanized tire member is measured by the use of the detectors and control means, and the shortage in length of the tire member relative to the circumferential length of the forming drum is obtained by the arithmetic operation with the aid of signals from the detectors. Therefore, a very expensive and large type control system is necessary. Moreover, every time sizes of tires are changed, the circumferential length of the forming drum must be manually or automatically set with a very high accuracy, and the operation is troublesome and the control is complicated. Further, the ends of the tire member cannot be properly joined due to accumulated errors, such as errors in measuring lengths of tire members and differences between the set lengths and actual circumferential lengths of the drums.